Water loss reducing pasting mats for lead-acid batteries

ABSTRACT

A non-woven fiber mat for lead-acid batteries is provided. The non-woven fiber pasting mat includes glass fibers coated with a sizing composition; a binder composition; and one or more additives. The additives reduce water loss in lead-acid batteries.

RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.15/316,238, filed on Dec. 5, 2016, which is the U.S. national stageentry of PCT/US15/36141, filed on Jun. 17, 2015, which claims priorityto U.S. Provisional Application No. 62/013,099, filed on Jun. 17, 2014,all of which are hereby incorporated by reference in their entirety.

FIELD

The general inventive concepts relate to lead-acid batteries, and moreparticularly to the incorporation of active chemistry to address waterloss in lead-acid batteries.

BACKGROUND

Lead-acid batteries are among the most commonly used rechargeablebatteries due to their ability to supply high currents, while having arelatively low production cost. Lead-acid batteries are largely used inthe automotive starting, lighting, and ignition (SLI) sector and inother industrial sectors due to their high discharge capability.Conventional lead-acid batteries include a positive electrode (PbO₂plate) and a negative electrode (spongy Pb plate) immersed in a sulfuricacid electrolyte. A separator may be disposed between the positive andnegative plates. Separators function to not only provide mechanicalseparation between the positive and negative plates, but to also preventshorting between electrodes and allow ionic conduction. There are manydifferent forms of electrodes. In some instances, the electrodes consistof lead or lead alloy plates having a grid-like structure. An activematerial paste consisting of lead oxides and sulfuric acid is used tofill the holes in the grid of the positive plate. The active materialpaste is porous, thereby allowing the acid to react with the lead insidethe plate, which increases the surface area of the electrodes. The pasteis dried and the positive and negative electrodes are activated by anelectrochemical process.

During discharge, the lead dioxide and lead react with the electrolyteof sulfuric acid to create lead sulfate, water, and energy. When thebattery is charged, the cycle is reversed and the lead sulfate and waterare electrochemically converted to lead, lead oxide and sulfuric acid byan external electrical charging source. If current is being provided tothe battery faster than lead sulfate can be converted, a phenomenoncalled “gassing” begins before all the lead sulfate is converted, thatis, before the battery is fully charged. Gassing consists of a sidereaction that disassociates the water into hydrogen and oxygen andreleases them into the atmosphere. Gassing particularly occurs duringexcessive charging. Such gassing causes water loss, which can lead to aneventual dry out and decline in capacity. Therefore, conventionallead-acid batteries must be replenished with water periodically.

SUMMARY

Various aspects of the general inventive concepts are directed to afiber pasting mat for lead-acid batteries. The pasting mat includes aplurality of fibers coated with a sizing composition, a bindercomposition, and one or more additives, wherein said additives reducewater loss in lead-acid batteries.

In some exemplary embodiments, the binder composition is an acrylicbinder, a styrene acrylonitrile binder, a styrene butadiene rubberbinder, a urea formaldehyde binder, an epoxy binder, a polyurethanebinder, a phenolic binder, a polyester binder, or a mixture thereof.

In some exemplary embodiments, the additives are included in at leastone of the sizing composition and the binder composition.

In some exemplary embodiments, the additives include one or more ofrubber additives, rubber derivatives, aldehyde, aldehyde derivatives,metal salts, fatty alcohol ethyoxylates (alkoxylated alcohols withterminal OH group), ethylene-propylene oxide block copolymers, sulphateesters (alkylsulphates and alkylether sulphates), sulphonate esters(alkyl and olefin sulphonates), phosphate esters, sulphosuccinates,polyacrylic acid, polyaspartic acid, perfluoroalkylsulfonic acid,polyvinylalcohol, lignin, lignin derivatives, phenol formaldehyde resin,cellulose, and wood flour.

Various aspects of the general inventive concepts are directed to alead-acid battery that includes at least one positive electrode and atleast one negative electrode, both of which are immersed within anelectrolyte, and at least one non-woven fiber pasting mat at leastpartially covering a surface of at least one of the positive andnegative electrode. The non-woven fiber pasting mat may include aplurality of glass fibers coated with a sizing composition, a bindercomposition, and one or more additives, wherein said additives reducewater loss in the lead-acid battery.

Yet additional aspects of the general inventive concepts are directed toa method of forming a non-woven fiber pasting mat for use in a lead-acidbattery. The method includes dispersing a plurality of glass fibers intoan aqueous slurry. The fibers may be coated with a sizing composition.The binder may then be applied on the deposited slurry after which thebinder-coated slurry is heated, thereby curing said binder and forming anon-woven fiber pasting mat. In some exemplary embodiments, the pastingmat includes one or more additives included in at least one of thesizing composition and the binder.

Additional features and advantages will be set forth in part in thedescription that follows, and in part may be apparent from thedescription, or may be learned by practice of the exemplary embodimentsdisclosed herein. The objects and advantages of the exemplaryembodiments disclosed herein will be realized and attained by means ofthe elements and combinations particularly pointed out in the appendedclaims. It is to be understood that both the foregoing summary and thefollowing detailed description are exemplary and explanatory only andare not restrictive of the general inventive concepts as disclosedherein or as otherwise claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments of the invention will be apparent from the moreparticular description of certain example embodiments of the inventionprovided below and as illustrated in the accompanying drawings.

FIG. 1 illustrates a voltammogram graph produced from a pure acidelectrolyte and a pure Pb working electrode.

FIG. 2 illustrates a voltammogram of the potential shift that occurswhen additives are extracted from a pasting mat via the acidelectrolyte.

FIG. 3 graphically illustrates the electrical resistance normalized over0.10 mm thickness for exemplary non-woven fiber mats prepared inaccordance with the present invention.

DETAILED DESCRIPTION

Various exemplary embodiments will now be described more fully, withoccasional reference to any accompanying drawings. These exemplaryembodiments may, however, be embodied in different forms and should notbe construed as limited to the descriptions set forth herein. Rather,these exemplary embodiments are provided so that this disclosure will bethorough and complete, and will convey the general inventive concepts tothose skilled in the art.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which these exemplary embodiments belong. The terminologyused in the description herein is for describing particular exemplaryembodiments only and is not intended to be limiting of the exemplaryembodiments.

As used in the specification and the appended claims, the singular forms“a,” “an,” and “the” are intended to include the plural forms as well,unless the context clearly indicates otherwise. All publications, patentapplications, patents, and other references mentioned herein areincorporated by reference in their entirety.

Unless otherwise indicated, all numbers expressing quantities ofingredients, reaction conditions, and so forth used in the specificationand claims are to be understood as being modified in all instances bythe term “about.” Accordingly, unless indicated to the contrary, thenumerical parameters set forth in the specification and attached claimsare approximations that may vary depending upon the desired propertiessought to be obtained by the present exemplary embodiments. At the veryleast, and not as an attempt to limit the application of the doctrine ofequivalents to the scope of the claims, each numerical parameter shouldbe construed in light of the number of significant digits and ordinaryrounding approaches.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the exemplary embodiments are approximations, thenumerical values set forth in the specific examples are reported asprecisely as possible. Any numerical value, however, inherently containscertain errors necessarily resulting from the standard deviation foundin their respective testing measurements. Every numerical range giventhroughout this specification and claims will include every narrowernumerical range that falls within such broader numerical range, as ifsuch narrower numerical ranges were all expressly written herein.

The general inventive concepts relate to a non-woven fiber mat, such asa pasting mat or a retainer mat for lead-acid batteries, or otherbatteries. The non-woven fiber mat may comprise a plurality ofreinforcement fibers combined in the form of a sheet. In some exemplaryembodiments, the reinforcement fibers are made from glass. However, thereinforcement fibers may also include synthetic fibers, or a combinationof glass fibers and synthetic fibers. The term synthetic fiber, as usedherein, is intended to include any man-made fiber having suitablereinforcing characteristics including fibers made from suitable polymerssuch as, for example, polyesters, polyolefins, nylons, aramids,poly(phenylene sulfide), and suitable non-glass ceramics such as, forexample, silicon carbide (SiC) and boron nitride.

The glass fibers may be formed from any type of glass suitable for aparticular application and/or desired product specifications, includingconventional glasses. Non-exclusive examples of glass fibers includeA-type glass fibers, C-type glass fibers, G-type glass fibers, E-typeglass fibers, S-type glass fibers, E-CR-type glass fibers (e.g.,Advantex® glass fibers commercially available from Owens Corning),R-type glass fibers, wool glass fibers, biosoluble glass fibers, andcombinations thereof, which may be used as the reinforcing fibers. Insome exemplary embodiments, the glass fibers are durable in an acidicenvironment.

The non-woven fiber mat may comprise a single mat, or more than one mat,e.g., two, three, four, or five mats, which may be employed in a singlelead-acid battery. Each non-woven fiber mat may comprise a single layer,or may be composed of more than one layer, e.g., two, three, four, orfive layers. In some exemplary embodiments, the non-woven fiber matcomprises a non-woven glass fiber pasting mat. In some exemplaryembodiments, the non-woven fiber mat comprises a non-woven glass fiberretainer mat.

In some exemplary embodiments, the glass fibers have a diameter that isat least 0.2 microns, such as from about 0.2 microns to about 30microns. In some exemplary embodiments, the glass fibers have a diameterfrom about 1 micron to about 25 microns, or from about 6 microns toabout 23 microns.

Glass fibers may be formed by drawing molten glass into filamentsthrough a bushing or orifice plate and applying a sizing composition tothe filaments. The sizing composition provides protection to the fibersfrom interfilament abrasion and promotes compatibility between the glassfibers and the matrix in which the glass fibers are to be used. Afterthe sizing composition is applied, the fibers may be gathered into oneor more strands and wound into a package or, alternatively, the fibersmay be chopped while wet and collected. The collected chopped strandsmay then be dried and optionally cured to form dry chopped fibers orthey can be packaged in their wet condition as wet chopped fibers.

In some exemplary embodiments, the sizing compositions used to coatglass fibers are aqueous-based compositions, such as suspensions oremulsions. The suspension or emulsion has a solids content that may becomposed of one or more of a film former, a coupling agent, a lubricant,and a surfactant. A film former may work to hold individual filamentstogether to form fibers, and protect the filaments from damage caused byabrasion. Acceptable film formers include, for example, polyvinylacetates, polyurethanes, modified polyolefins, polyesters epoxides, andmixtures thereof. A coupling agent may be included in a sizingcomposition to enhance the adhesion of the sizing compositions withmatrix material when forming a composite, to improve the compositeproperties. In some exemplary embodiments, the coupling agent is anorganofunctional silane.

Additional additives may be included in the sizing compositions,depending on the intended application. Such additives include, forexample, anti-statics, wetting agents, antioxidants, and pH modifiers.

The non-woven glass fiber mat may be produced using either continuous orchopped fiber strands, or a combination of continuous and chopped fiberstrands. The chopped fiber strands have lengths that may vary dependingon a particular process and/or application. In some exemplaryembodiments, the chopped fibers have a length of about 3 to about 60 mm.

The non-woven glass fiber mats may be formed in accordance with any ofthe known methods for producing glass fiber mats, such as, for example,dry-laid processing and wet-laid processing. In a dry-laid process,fibers are chopped and air blown onto a conveyor and a binder is thenapplied and dried and/or cured to form a mat. Dry-laid processes may beparticularly suitable for the production of highly porous mats havingbundles of glass fibers. In a wet-laid process, a water slurry “whitewater” is provided into which glass fibers are dispersed. The whitewater may contain dispersants, viscosity modifiers, defoaming agents, orother chemical agents. The slurry containing the glass fibers is thendeposited onto a moving screen and a substantial amount of the water isremoved therefrom. A binder may then be applied to the deposited fibers,after which heat is applied to remove any remaining water and to curethe binder thereby forming a non-woven glass fiber mat.

The binder may be any type of binder composition, such as an acrylicbinder, a styrene acrylonitrile binder, a styrene butadiene rubberbinder, a urea formaldehyde binder, an epoxy binder, a polyurethanebinder, a phenolic binder, a polyester binder, or a mixture thereof.Exemplary acrylic binders may include, for example, polyacrylic acid,ethylacrylate, methacrylate, methylmethacrylate, styrene acrylate, andmixtures thereof. In some exemplary embodiments, the binder is athermoset acrylic binder formed of polyacrylic acid and at least onepolyol, such as for example, triethanolamine or glycerine. The bindermay optionally contain one or more additional components for improvedprocessability and/or product performance, such as dyes, oils, fillers,colorants, UV stabilizers, coupling agents (e.g., aminosilanes),lubricants, wetting agents, surfactants, and/or antistatic agents.

In some exemplary embodiments, the binder comprises about 1 to about 30weight percent of the total dry weight of the glass fiber mat. In otherexemplary embodiments, the binder comprises about 8 to about 25 weightpercent of the total dry weight of the glass fiber mat. In someexemplary embodiments, the binder comprises about 18 to 25 weightpercent of the total dry weight of the glass fiber mat.

Rechargeable batteries have both a theoretical decomposition voltage andan effective decomposition voltage at which point the decomposition ofwater begins. The effective decomposition voltage is usually higher thanthe theoretical decomposition voltage and depends on the electrodematerial used. The difference between the theoretical and effectivedecomposition voltages is known as the battery's overpotential. Lead isknown for its high hydrogen overpotential, such that reactions,including the transformation of lead sulphate to lead, occur easier thanthe water decomposition. However, grids are often made of lead alloysconsisting of noble metal mixtures like calcium, antimony, silver, tin,etc., which have very low overpotential, such that a high level ofhydrogen gas can evolve at the same potential difference.

In some exemplary embodiments, the non-woven glass fiber mats aretreated with one or more additives that are capable of shifting thehydrogen overpotential for gassing on the negative plate from reactionswith the noble metals and, thus, suppressing hydrogen evolution. Theadditive may be included as an additive to the sizing composition, anadditive to the binder composition, or as an additive to both the sizingand binder compositions. In some exemplary embodiments, the non-wovenmat is a pasting mat, such that by including the additives in thepasting mat, via the sizing and/or binder composition, the additives maybe delivered directly to the surface of the electrodes, particularly thenegative electrode, where the additives may directly influence theelectrode surface reactions, thereby shifting the hydrogen gassingpotential of the negative electrode and reducing the side reactions thatcause gassing.

In some exemplary embodiments, the additives include one or more organiccompounds, such as rubber additives, rubber derivatives, aldehydes,aldehyde derivatives, metal salts, fatty alcohol ethyoxylates(alkoxylated alcohols with terminal OH group), ethylene-propylene oxideblock copolymers, sulphate esters (alkylsulphates and alkylethersulphates), sulphonate esters (alkyl and olefin sulphonates), phosphateesters, sulphosuccinates, polyacrylic acid, polyaspartic acid,perfluoroalkylsulfonic acid, polyvinylalcohol, lignin, ligninderivatives, phenol formaldehyde resin, cellulose, and wood flour.

In some exemplary embodiments, the additives comprise about 0.1 to about30 weight percent of the non-woven fiber mat. In other exemplaryembodiments, the additives comprise about 3.0 to 25 weight percent ofthe non-woven fiber mat.

In some exemplary embodiments, the binder itself may act as an additivecapable of influencing the surface of the electrodes. For example, apolyacrylic acid binder may also be capable of shifting the hydrogenoverpotential for gassing on the negative plate by reacting with thenoble metals and suppressing hydrogen evolution. Accordingly, in someexemplary embodiments, the “additives” may comprise all or substantiallyall of the binder composition.

By incorporating the additives directly into the sizing compositionand/or into the binder composition, the additives are directly exposedto the surface of the lead alloy grids. The additives have a limitedsolubility in the acid electrolyte and are released slowly during useonce the non-woven fiber mat is in the acid electrolyte and the platesbecome active. Utilizing the non-woven fiber mat as a pasting mat allowsfor the slow release of the active compounds from the pasting matprovides the additives with direct contact with the surface of theelectrode. The solubility of the additives may be affected by thetemperature, and fairly high temperatures are reached in batteryformation. The high temperatures may initiate leaching from the pastingmat to the surface of the negative electrode.

Organic additives are prone to oxidation, which is undesirable as it maydestroy their ability to react with the noble metals, and theiroxidation products may be harmful for the battery. Oxidation mainlytakes place at the positive plate because lead dioxide (PbO₂) is a verystrong oxidizer, especially in combination with sulphuric acid. Byapplying the organic additives to the negative plate via the non-wovenpasting mat, the distance to the positive plate is maximized and theorganic active compounds have a lower risk of oxidation at the positiveplate compared to applications that introduce chemistries directly intothe electrolyte.

The additives are released slowly during use once the non-woven fibermat is in the electrolyte acid and the plates become active. In someexemplary embodiments, the additives leach out of the non-woven fibermat and are capable of reacting with the noble metals in the lead alloygrid of the negative plate, which ensures that the molecules areunavailable for side reactions that lead to gassing. The reactions shiftthe hydrogen gassing potential to a higher overpotential. In someexemplary embodiments, the use of the additives in the sizing and/orbinder composition shifts the hydrogen gassing potential of the negativeplate by at least −30 mV, or at least −50 mV, or at least −80 mV. Insome exemplary embodiments, the inclusion of the additives shifts thehydrogen gassing potential by at least −100 mV. By increasing theoverpotential of the battery cell, the amount of current that isconsumed when perpetuating the water decomposition reactions issignificantly lessened. Thus, a battery can benefit from using an entirecharge, which further improves the life of the battery.

In some exemplary embodiments, treating the electrode surface withwater-loss reducing additives by incorporating the additives into thesizing composition and/or binder composition of a pasting matdemonstrates an improvement in life cycle of at least about 10%, or atleast about 25%, over otherwise similar lead-acid battery cells thateither have no pasting mat or include a cellulose-based pasting mat.

The process of preparing a lead-acid battery comprises forming one ormore battery cells, which each include a positive plate electrode havinga first face and a second face, opposite the first face, a negativeplate electrode having a first face and a second face, opposite thefirst face, and a separator disposed therebetween. The positiveelectrode includes a grid containing lead alloy material. A positiveactive material, such as lead dioxide, is coated on the grid of thepositive electrode. The negative plate electrode also includes a grid oflead alloy material that is coated with a negative active material, suchas lead. The positive and negative plate electrodes are immersed in anelectrolyte that may include sulfuric acid and water. The separator maybe positioned between the positive and negative plate electrodes tophysically separate the two electrodes while enabling ionic transport.

The non-woven fiber pasting mat disclosed herein may be positioned topartially or fully cover at least one surface of the negative plateelectrode. In some exemplary embodiments, pasting mats are positioned oneach side of the negative plate electrode. In some exemplaryembodiments, the use of glass fibers in the non-woven pasting matprovides added dimensional stability to the negative plates duringcharge and discharge. During discharge, the negative plates generallyincrease in volume and then shrink significantly during a chargingcycle, due to the different crystals formed. The improved dimensionalstability provided by the glass fiber pasting mat reduces the expansionand/or shrinkage, which in turn leads to an improved battery life bypreventing active mass from shedding from the grid and maintaining goodcontact between the active material and the grid to guarantee chargeacceptance and current flow. In some exemplary embodiments, a non-wovenfiber pasting mat is positioned to partially or fully cover at least onesurface of the positive plate, to function as a retainer by holding theactive material in place on the positive plate while also providingimproved dimensional stability. In some exemplary embodiments, pastingmats are positioned on each side of the positive plate electrode. Insome exemplary embodiments, non-woven fiber pasting mats are positionedon both sides of each of the positive and negative plates.

In other exemplary embodiments, the non-woven fiber mat functions as aretainer mat and is positioned in contact with at least one side of theseparator.

In some exemplary embodiments, incorporation of additives in the sizingand/or binder composition as disclosed herein improves the electricalresistance of the pasting mat. The electrical resistance is the ionicresistance a mat generates when placed in a certain density of sulphuricacid.

The following examples are meant to better illustrate the presentinvention, but are not intended to limit the general inventive conceptsin any way.

EXAMPLES Example 1

Comparative Examples 1-4 include conventional pasting mats preparedwithout the use of the water-loss reducing additives disclosed herein.The mat of Comparative Example 1 was formed using cellulose fibers. Themat of Comparative Example 2 was formed using microglass. The mat ofComparative Example 3 was formed as a glass non-woven mat, comprisingchopped fibers with a larger diameter than the microglass. The glassfiber diameter may be in the range of 6 μm to 16 μm and the fibers arebonded with an acid resistant acrylic based binder. The mat ofComparative Example 4 was formed using polyester fibers made via awet-laid process or spunbond process.

Examples 1-6 comprise pasting mats formed in accordance with embodimentsof the present invention. The mat of Example 1 was formed using a 50:50mixture of 6.5 μm-6 mm and mm glass fibers bonded with carboxylatedstyrene butadiene latex. The final weight of the mat was 27 g/m² andcomprised about 18 weight percent binder.

The mat of Example 2 was formed using 13 μm-18 mm glass fibers bondedwith a nonionic, self-crosslinking acrylic polymer. A block copolymer ofpolypropyleneglycol and polyethyleneglycol (approximately 0.04 g/m²) wasadded to the binder. The final mat weight was 31 g/m².

The mat of Example 3 was formed using 11 mm glass fibers bonded with aself-crosslinking acrylic polymer. The final weight of the mat was 28g/m² and comprised about 20 weight percent binder. An aldehyde,particularly vanillin, was added to the binder, around 1 g/m².

The mat of Example 4 was formed using a 50:50 mixture of 6.5 μm-6 mm and11 μm-12 mm glass fibers bonded with an acrylic polymer to form a basemat having a weight of 26 g/m². This base mat was then treated with apolyacrylic acid solution to a final weight of 34 g/m².

The mat of Example 5 was formed using a 50:50 mixture of 6.5 μm-6 mm and11 μm-12 mm glass fibers bonded with an acrylic polymer to form a basemat having a weight of 26 g/m². This base mat was then treated with apolyaspartic acid solution to a final weight of 31 g/m².

The mat of Example 6 was formed using 11 μm-30 mm glass fibers bondedwith a self-crosslinking acrylic polymer binder. The final pasting mathad a weight of 27 g/m² and comprised about 20 weight percent binder. Alignosulphonate was added to the binder, around 2 g/m².

Each of the pasting mats described above was submitted to an acidextraction process (24 hours, 70° C., and acid density of 1.21 g/cm³).The extraction acid was then used to record the cyclic voltammogram andhydrogen potential shift. The results are listed below in Table 1.

TABLE 1 Exemplary Pasting Mats. Hydrogen Binder Tensile shift PastingWeight weight Thickness strength potential mat Additive (g/m²) percent(mm) (N/50 mm) (mv) Comparative Cellulose — 13 — 0.05 30 −50 Example 1Comparative Microglass — 25 30 0.16 16 13 Example 2 Comparative Glass —22 35 0.17 70 −12 Example 3 Comparative polyester — 25 100 0.05 35 −5Example 4 Example 1 Glass — 27 18 0.22 87 −33 Example 2 Glass Blockcopolymer of 31 19 0.23 62 −107 polypropyleneglycol andpolyethyleneglycol Example 3 Glass Aldehyde (vanillin) 28 20 0.23 65−108 Example 4 Glass Polyacrylic acid 34 19 0.2 80 −118 Example 5 GlassPolyaspartic acid 32 18 0.2 72 −92 Example 6 Glass lignosulphonate 27 200.21 70 −30

The results of Table 1 illustrate the hydrogen potential shift thatoccurs when the water-loss reducing additives disclosed herein areincluded in the sizing and/or binder composition of the non-woven fiberpasting mats.

Example 2

The evolution of hydrogen gas was tested by screening how differenttypes of pasting mats effect the hydrogen potential using cyclicvoltammetry. During cyclic voltammetry, a working electrode potential isramped linearly versus time. When the working electrode reaches a setpotential, the electrode's potential ramp is inverted. The current atthe working electrode is then plotted versus the applied voltage to givethe cyclic voltammogram trace.

Exemplary pasting mats were subjected to an acid extraction procedure toassure leaching of the active ingredients. The measurements were carriedout in a glass vessel with a three electrode arrangement (i.e., aworking electrode, a reference electrode, and counter electrode). Thetemperature was held at 23° C. The reference electrode was an Hg/HgSO₄electrode and all potentials reported were with respect to thiselectrode. The electrolyte used in each example was sulphuric acid witha density of 1.21 g/cm³.

FIG. 1 illustrates a typical voltammogram graph produced from a pureacid electrolyte and a pure Pb working electrode. The voltammogramillustrates the different electrode reactions that take place at theelectrode/electrolyte interface. The anodic peak at −0.88 mV and thecathodic peak at around −0.98 mV are characteristic for the leadoxidation and lead sulphate reduction respectively. The increase incathodic current at more negative potentials starting around −1.400 mVis attributed to the evolution of hydrogen.

FIG. 2 illustrates a voltammogram of the potential shift that occurswhen additives are extracted from a pasting mat via the acidelectrolyte. As illustrated in FIG. 2, the additives in the inventivepasting mat (labeled Life Mat and containing fatty alcohol ethyoxylatesadditives) shift the hydrogen potential about −80 mV compared to acomparable pasting mat that does not include additives as describedherein.

Example 2

A variety of non-woven fiber pasting mats were prepared to have variousfiber types, weights, and thicknesses. Table 2 below illustrates theproperties of these mats.

TABLE 2 Properties of Fiber Mats. Electrical air LOI Resistance FiberWeight Thickness permeability measured (per .01 ER/0.1 Sample type(grams/m²) (mm) (1/m²s) (%) mm) mm 1 glass 25.1 0.19 7420 12.0 11.7 6.172 glass 22.9 0.205 6780 21.1 13.7 6.66 3 glass 24.6 0.22 8330 16.5 16.37.43 4 glass 24.2 0.165 5190 18.9 14.1 8.53 5 glass 131.5 0.9 2400 14.137.8 4.20 6 glass 105.3 0.95 4420 15.7 27.1 2.85 7 glass 117.3 0.84 240014.7 36.7 4.36 8 glass 23.8 0.19 6930 23.0 13.8 7.24 9 glass 23.5 0.27650 11.9 12.0 6.02 10 glass 84.5 0.61 3130 15.9 26.0 4.26 11 glass 53.80.42 4020 17.8 30.1 7.16 12 glass 39.7 0.33 5130 18.9 23.1 7.01 12 glass69.1 0.38 1790 18.2 26.0 6.85 13 glass 48.2 0.42 4246 11.6 19.6 4.66 14glass 41.8 0.4 4488 18.8 15.4 3.84 15 glass 47.5 0.42 4114 27.9 24.35.78 16 glass 51 0.42 3982 33.5 46.2 11.01 17 glass 40.3 0.41 5104 16.914.2 3.46 18 glass 43.7 0.41 4378 19.4 14.0 3.41 19 glass 43.6 0.41 374020.1 22.0 5.37 20 glass 50.1 0.41 1606 19.8 21.8 5.33 21 glass 39.6 0.45786 15.4 7.7 1.94 Comparative polyester 25 0.06 1570 100.0 26.9 44.77Example-1 Comparative polyester 18.5 0.08 2850 100.0 19.7 24.59Example-2 Comparative glass 19.5 0.17 5540 38.0 26.1 15.37 Example -3

As illustrated in Table 2, the electrical resistance for the non-wovenfiber mats was lowest for glass fiber mats prepared in accordance withthe present invention. The electrical resistance, when normalized over0.10 mm thickness, is lowest for the non-woven glass fiber mats preparedin accordance with the present invention. Each of samples 1-21demonstrates electrical resistance, normalized over 0.1 mm, of lowerthan 15/0.1 mm. In some exemplary embodiments, the glass fibers may havean electrical resistance of less than 10/0.1 mm. The normalizedelectrical resistances of the examples illustrated in Table 2 arefurther compared in FIG. 1, which shows that each of the non-woven glassfiber mats formed according to the present invention (OC1-13 and labexamples) demonstrates an electrical resistance normalized over 0.1 mmthat is far less than 15.

The general inventive concepts have been described above bothgenerically and with regard to various exemplary embodiments. Althoughthe general inventive concepts have been set forth in what is believedto be exemplary illustrative embodiments, a wide variety of alternativesknown to those of skill in the art can be selected within the genericdisclosure. The general inventive or otherwise apparent concepts are nototherwise limited, except for the recitation of the claims set forthbelow.

1. A lead-acid battery comprising: a positive electrode having a firstface and a second face opposite said first face and a negative electrodehaving a first face and a second face opposite said first face, whereineach of said positive and negative electrode is immersed within anelectrolyte; a fiber pasting mat at least partially covering at leastone of said first and second faces of at least one of said positive andsaid negative electrode, said fiber pasting mat comprising: a pluralityof fibers coated with a sizing composition; a binder composition; andone or more additives, said one or more additives comprising one or moreof rubber additives, rubber derivatives, aldehyde, aldehyde derivatives,metal salts, fatty alcohol ethyoxylates (alkoxylated alcohols withterminal OH group), ethylene-propylene oxide block copolymers, sulphateesters (alkylsulphates and alkylether sulphates), sulphonate esters(alkyl and olefin sulphonates), phosphate esters, sulphosuccinates,polyacrylic acid, polyaspartic acid, perfluoroalkylsulfonic acid,polyvinylalcohol, lignin, lignin derivatives, phenol formaldehyde resin,cellulose, and wood flour, wherein said one or more additives areoperable to reduce water loss in the lead-acid battery.
 2. The lead-acidbattery of claim 1, wherein said fibers comprise one or more of glassfibers, polyester fibers, polyolefin fibers, nylon fibers, aramidfibers, poly(phenylene sulfide) fibers, carbon fibers, silicon carbide(SiC) fibers, and boron nitride fibers.
 3. The lead-acid battery ofclaim 2, wherein said glass fibers have an average diameter of about 0.2microns to about 30 microns.
 4. The lead-acid battery of claim 2,wherein said glass fibers have an average diameter of about 1 micron toabout 25 microns.
 5. The lead-acid battery of claim 2, wherein saidglass fibers are chopped fibers having an average length of betweenabout 3 mm and about 60 mm.
 6. The lead-acid battery of claim 1, whereinsaid additive is included in at least one of the sizing composition andthe binder composition.
 7. The lead-acid battery of claim 1, whereinsaid additive comprises about 0.1 weight percent to about 30 weightpercent of said fiber pasting mat.
 8. The lead-acid battery of claim 1,wherein said additive is capable of shifting the hydrogen gassingpotential of the negative electrode by at least −30 mV.
 9. The lead-acidbattery of claim 1, wherein said fiber pasting mat has an electricalresistance of less than about 15/0.1 mm.
 10. The lead-acid battery ofclaim 1, wherein a fiber pasting mat is at least partially covering eachof said first and second faces of said positive electrode.
 11. Thelead-acid battery of claim 1, wherein a fiber pasting mat is at leastpartially covering each of said first and second faces of said negativeelectrode.
 12. A method of forming a non-woven fiber mat for use in alead-acid battery, said method comprising: dispersing a plurality offibers into an aqueous slurry, said fibers being coated with a sizingcomposition; depositing said slurry onto a moving screen; applying abinder onto the deposited slurry; and heating said binder-coated slurry,to remove excess water and cure said binder, thereby forming a non-wovenfiber mat, wherein said non-woven fiber mat includes one or moreadditives included in at least one of said sizing composition and saidbinder, said additives including one or more of rubber additives, rubberderivatives, aldehyde, aldehyde derivatives, metal salts, fatty alcoholethyoxylates (alkoxylated alcohols with terminal OH group),ethylene-propylene oxide block copolymers, sulphate esters(alkylsulphates and alkylether sulphates), sulphonate esters (alkyl andolefin sulphonates), phosphate esters, sulphosuccinates, polyacrylicacid, polyaspartic acid, perfluoroalkylsulfonic acid, polyvinylalcohol,lignin, lignin derivatives, phenol formaldehyde resin, cellulose, andwood flour.
 13. A non-woven retainer mat for contacting a separator in alead-acid battery comprising: a plurality of fibers coated with a sizingcomposition; a binder composition; and one or more additives, said oneor more additives including one or more of rubber additives, rubberderivatives, aldehyde, aldehyde derivatives, metal salts, fatty alcoholethyoxylates (alkoxylated alcohols with terminal OH group),ethylene-propylene oxide block copolymers, sulphate esters(alkylsulphates and alkylether sulphates), sulphonate esters (alkyl andolefin sulphonates), phosphate esters, sulphosuccinates, polyacrylicacid, polyaspartic acid, perfluoroalkylsulfonic acid, polyvinylalcohol,lignin, lignin derivatives, phenol formaldehyde resin, cellulose, andwood flour, wherein said one or more additives are operable to reducewater loss in a lead-acid battery.
 14. The non-woven retainer mat ofclaim 13, wherein said one or more additives are included in at leastone of the sizing composition and the binder composition.
 15. Thenon-woven retainer mat of claim 13, wherein said one or more additivescomprise about 0.1 weight percent to about 30 weight percent of thenon-woven fiber pasting mat.
 16. The non-woven retainer mat of claim 13,wherein said one or more additives include one or more ofethylene-propylene oxide block copolymers, aldehydes, polyacrylic acid,and polyaspartic acid.
 17. The non-woven retainer mat of claim 13,wherein said non-woven retainer mat is capable of increasing the lifecycle of a lead-acid battery by at least 10% compared to an otherwisecomparable lead-acid battery without said non-woven retainer mat.
 18. Alead-acid battery comprising: a positive electrode, a negativeelectrode, and a separator, having a first face and a second faceopposite thereto, disposed therebetween, wherein each of said positiveelectrode, negative electrode, and separator is immersed within anelectrolyte; and a non-woven retainer mat according to claim 13 at leastpartially covering at least one of said first and second face of saidseparator.